import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
+import static java.util.Arrays.asList;
import java.util.ArrayList;
import java.util.Comparator;
import com.google.common.base.Function;
import com.google.common.base.Optional;
+import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.Collections2;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableList;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
}
};
+ /** Function that flattens the given album and all albums beneath it. */
+ public static final Function<Album, List<Album>> FLATTENER = new Function<Album, List<Album>>() {
+
+ @Override
+ public List<Album> apply(Album album) {
+ List<Album> albums = new ArrayList<Album>();
+ albums.add(album);
+ for (Album subAlbum : album.getAlbums()) {
+ albums.addAll(FluentIterable.from(ImmutableList.of(subAlbum)).transformAndConcat(FLATTENER).toList());
+ }
+ return albums;
+ }
+ };
+
+ /**
+ * Filter that removes all albums that do not have any images in any album
+ * below it.
+ */
+ public static final Predicate<Album> NOT_EMPTY = new Predicate<Album>() {
+
+ @Override
+ public boolean apply(Album album) {
+ return FluentIterable.from(asList(album)).transformAndConcat(FLATTENER).anyMatch(new Predicate<Album>() {
+
+ @Override
+ public boolean apply(Album album) {
+ return !album.getImages().isEmpty();
+ }
+ });
+ }
+ };
+
/** The ID of this album. */
private final String id;